Gunderam Defense: what should Black play?

In the Gunderam Defense after White introduces an English-style pawn clamp with c4, Black's statistically soundest response according to the engine is c5. This flank advance establishes a symmetrical grip on the center, yielding an engine evaluation of +0.77. Although chosen in only 7.8% of recorded games (632 recorded), it offers Black a sharper counter to White's space advantage than the more passive continuations.

Strategic context of the c5 break

Playing c5 directly challenges White's control over the central d4 square and prevents an uncontested bind. The engine's illustrative continuation runs c5 b4 Nc6 b5 Nd4 Nc3, where White lashes out immediately on the queenside, and Black redirects a knight to the hole on d4. White scores 57.0% from this position, reflecting a persistent space advantage, yet the engine considers this Black's most resilient path.

Popular human alternatives

In practice, players opt for natural piece development and central reinforcement far more frequently than the engine's preferred pawn thrust. The most common move in the database is d6, appearing in 37.1% of games (3.0K recorded) with an evaluation of +1.01, often leading to d6 d4 exd4 Nxd4 Qxe4+ Be3. Developing moves are also prominent: Nf6 is selected in 29.6% of games (2.4K recorded, evaluated at +0.85) following the continuation Nf6 Nc3 Nc6 Be2 Nd4 d3, while Nc6 accounts for 20.8% of games (1.7K recorded, evaluated at +0.89) via Nc6 Be2 Nf6 Nc3 Nd4 d3. The kingside fianchetto setup with g6 represents 4.7% of games (384 recorded) and evaluates at +1.01 after g6 Nc3 Nf6 d4 exd4 Nxd4.